1. Field of the Invention
This invention relates to methods and apparatus for generating heat and electrical energy from aluminum particles or pieces by contact with certain electrolyte solutions, and more particularly, relates to such methods and apparatus where improved contact of the aluminum particles is achieved with improved electrical continuity.
2. Description of the Prior Art
In my above-identified parent application Ser. No. 843,155, there are disclosed methods and apparatus for generating heat and electrical energy from aluminum waste and other inexpensive aluminum products by contact of pieces of such aluminum products with aqueous electrolyte solutions. The aluminum is contacted with an acidic or alkaline aqueous electrolyte solution to produce aluminum hydroxide as a reaction product which reaction serves to generate heat and electricity. The method is carried out by provision of a reaction chamber into which the pieces of aluminum are introduced and reacted with the electrolyte solution. As a result of the reaction, electricity is generated, either directly by having the reaction chamber form part of an electrochemical cell, or indirectly by first generating hydrogen in the reaction chamber and thereafter consuming the hydrogen in a fuel cell. The heat generated in the reaction chamber is carried away by a circulating fluid and may be used for space heating or other applications. The aluminum hydroxide product is removed from the system and may be recycled in production of fresh aluminum. In this system, use is made of a packed bed aluminum anode in which the packing of the aluminum particles is effected only by the combined forces of gravity and pressure exerted by a downward flow of the electrolyte solution. There is, however, no disclosure of use of a positive downward pressure on the packed aluminum to achieve improved contact between the aluminum particles and resultant improved electrical continuity. The present invention provides these aspects and represents an improvement on the invention disclosed in my prior application. The entire disclosure of my prior application Ser. No. 843,155, filed Oct. 17, 1977, is incorporated herein by reference.
Reference is also made to my prior U.S. Pat. Nos. 3,540,932, 3,554,810, 3,788,899 and 3,969,144, all of which are concerned with contact of metals with electrolytes in electrochemical cells. All of these prior patents utilize aluminum sheets or plates and not particles or chunks of aluminum as in the present invention. These patents include the reaction of electrolytes with aluminum metal for the generation of electricity and heat and pertain to the so-called aluminum-air batteries as described, for example, in U.S. Pat. No. 3,554,810.
Subject matter of this type is also discussed in my prior publications, e.g. in "Proceedings, Fourth Intersociety Energy Conversion Engineering Conference," (American Institute of Chemical Engineers, New York, 1969), pages 904-910; "Journal of the Electrochemical Society," Vol. 109, No. 12, December, 1962, page 39; "Journal of the Electrochemical Society," Vol. 109, No. 12, December, 1962, pages 1125-1130; and, "Journal of the Electrochemical Society," Vol. 110, No. 4, April, 1963, pages 267-271.
In my copending application Ser. No. 813,483, filed July 7, 1977, there is disclosed the use of slurry-type aluminum anodes in conjunction with fluidized-bed air cathodes. Such slurry-type anodes should be capable of utilizing aluminum waste products after the latter had been cut up or otherwise comminuted into fine particles or chips suitable for being carried by an electrolyte into properly designed anode compartments. The particles of such a slurry-type anode represent one common form to which the various types of aluminum waste may be reduced in order to be suitable for electrochemical consumption yielding heat and electricity.
In none of these prior patents, applications or publications, however, are there disclosures for use of a packed aluminum anode as in the present invention wherein positive pressure is exerted on aluminum particles for increased efficiency.